Containers have been known in the art for dispensing fluids under pressure. The fluid may be expelled in the form of an aerosol spray, that is fine droplets. For the purposes of this invention, the term "aerosol" means "suspensions or dispersions of fine solid or liquid particles, foams, syrups, or powders in a gas." Alternatively, the fluid may be expelled in the form of a stream of liquid, rather than in an aerosol spray.
An example of one such device is shown in FIG. 1, The container 10 includes a container body, or can 12 that typically is cylindrical and hollow, and includes reservoir 14 for receipt of a quantity of a fluid 16, The cavity 14 is enclosed on its bottom end by bottom closure 18, and on its upper end by top closure 20, As illustrated, in FIG. 1, top closure 20 includes a first top closure portion 20a, and a second top closure portion 20b. Access opening 22 is formed in the upper closure 20 communicating with reservoir 14 for egress of the fluid 16 from one container.
One conventional dispensing system expels fluid from the container by means of a pump or like mechanism placed in communication with the fluid within a reservoir. In this case it is not necessary to place the fluid under pressure while in storage within the container. The following is nonexclusive list of commercially available pump mechanisms for expelling a fluid from a container: Seamist and Euromist II Brand pumps available from Seaquist Dispensing, Division of Aptar Group of Cary, Ill., or with a Precision Aeropump Brand pump available from the Precision Valve Corporation of Yonkers, N.Y.
Frequently however, a dispensing system is utilized in which the fluid 16 in the reservoir is subject to pressure sufficient to expel the pressurized fluid through the access opening 22, to the exterior of the container body 12. Therefore, all of the components of the container forming the body 12 are constructed from materials, such as metallic materials, that may be effectively sealed in fluid tight relationship and withstand the pressure applied when filled with a fluid to be dispensed.
Such fluids 16 may include a mixture of a first fluid, such as indicated at 16 in FIG. 1, to be expelled from the container and a second fluid or phase, such as propellant 17, contained under pressure (such as in the head space 24 between the fluid 16 and the upper closure 20). It is this type of conventional spray container that is shown in FIGS. 1-3A and will be discussed herein in greater detail.
Referring now in particular to FIGS. 1 and 1A, sprayhead assembly 24 is mounted on the container 12 to control the dispensing of the fluid 16 from the container. Sprayhead assembly 24 includes actuator or push button 26. As illustrated in FIG. 1, actuator 26 includes stem 28, slidingly received in fluid tight relationship within access opening 22, and a top surface 30 adapted for convenient manual engagement.
Actuator 26 includes passageway 32 that extends from a first end 34, through stem 28 and the actuator body, to a second end 36. At least one slot 29 is formed in the stem adjacent to the first end 34 and communicating with passageway 32. The number, size, and length of the slots may be selected to regulate the flow of fluid through the actuator.
The second end 36 includes a nozzle portion 38 mounted at second end 36 of passageway 32, terminating in orifice 40 of reduced diameter to meter the flow of fluid therethrough. The stem 28 is connected to a valve 39 mounted within the container body. Valve 39 may be of any suitable design for controlling the flow of fluid from the reservoir 14.
Gasket 41 is mounted between valve 39 and upper closure 20b. Stem 28 is slidingly received with aperture 41a and sealed by gasket 41. Valve seat 42 is mounted within cavity 43 of the valve and is in contact with the end of stem 28. Spring 45 is mounted in cavity 43 of the valve and is in contact with valve seat 42. Spring 45 urges valve seat 42 in direction 46 to a closed, sealed position wherein the valve seat 42 seals against gasket 41, supported by top closure 20b. Slot 29 is located below gasket 41 to contain the fluid. If the actuator 26 is shifted in direction 48 against the force of spring 45, the valve is opened and fluid is able to flow past the valve seat 42 through slot 29 to the actuator passageway 32.
The type of actuator illustrated is "female" type. A "male" type of actuator (not shown) would include a tubular projection from the valve that would be received within a cooperative cavity in the actuator. However for purpose of this invention, the term "actuator" will be understood to include both male and female actuators, unless otherwise indicated.
The sprayhead assembly 30 also includes a tube 50 that provides fluid communication between first end 34 of the passageway 32 and the distal portion of the reservoir 14, and the fluid contained therein. Tube 50 includes passageway 54, extending to a second end 60 adjacent to the bottom of the reservoir 14. Valve 39 includes a passageway 52 that extends from passageway 54 of tube 50 to cavity 43.
When valve seat 42 is shifted to the open position, fluid 16 is propelled by the pressure of the vapor phase of propellant 17, acting in direction 64, into second end 60 of the tube 56, through the tube, through passageway 54 of tube 50, passageway 52 and cavity 43 of valve 39, through passageway 32 of actuator 26 outwardly from the container.
As shown more particularly in FIG. 2, passageway 32 includes two contiguous segments 32a and 32b. Segment 32a extends from first end 34 through passageway 32 and is generally axially aligned (along axis 66) therewith. Segment 32b projects from segment 32a along axis 68 and determines the direction of the fluid dispersion from the actuator. The segments 32a and 32b form elbow 70 at their juncture.
In the past, it has been common to provide a propellant such as a liquified gas, that is a volatile organic compound, dissolved, dispersed or otherwise comixed with the compound with the fluid 16 being a material that is dissolved in the compound. It has also been known that when dispensed, a portion of the fluid 16 has a tendency to be deposited on surface within the sprayhead assembly and then solidify through evaporation of the solvent and propellant. By "solidified" it is meant that the deposits are solid, semi-solid or viscous layers in which the material from the fluid is highly concentrated. These solidified deposits tend to accumulate at any obstruction or sharp change in geometry in the passageway through which the fluid is conveyed (as at 72 in FIGS. 3 and 3A). Such locations in conventional sprayhead assemblies are formed at elbow 70 of passageway 32, at the end of stem 28 engaged with valve 39, and the interior side of the nozzle member about the orifice, all shown in FIGS. 3 and 3A. In addition, it has been observed that the fluid also tends to fall back, solidify and accumulate on the exterior of the actuator body about the orifice 40, as shown in FIGS. 3 and 3A.
Although undesirable, this accumulation of solidified material has not presented a significant problem in the past. When the dispensing of the fluid with a volatile organic compound based solvent and propellant were resumed, the compound contained in the newly ejected fluid stream redissolved or redispersed the accumulated material and thus prevented substantial interference with, or blockage of, the operation of the container.
More recently, concern over environmental effects of the use of volatile organic compounds has made the use of other solvents, such as water, more desirable. It has been observed however, that water dissolvable and/or dispersable fluids that accumulate within the passageway 32 or above the actuator are generally not redispersed or redissolved when dispensing of the fluid is resumed. The accumulation shown in FIGS. 3 and 3A continues to increase to the point where significant restriction of the passageway, or even outright blockage, occurs with clear detrimental effect on the operation of the container.
Thus, it is desirable to provide an actuator for a fluid dispenser that attenuates accumulations of solidified material within the passageway of the actuator, particularly with water based fluids.